CAS

Chemical Abstracts Service (CAS), a division of the American Chemical Society, is the world’s authority for chemical information. Our secure databases (including CAS REGISTRYSM, the gold standard for substance information) are curated and quality-controlled by CAS scientists, and are recognized by chemical and pharmaceutical companies, universities, government organizations, and patent offices around the world as authoritative and comprehensive. By combining these databases with advanced retrieval and analysis technologies (in products and services such as SciFinder®, STN®, and Science IP®), CAS delivers the most current, complete, and cross-linked digital information environment for scientific research.

http://www.cas.org/